Animals such as mammals and birds are often susceptible to parasite infestations/infections. These parasites may be ectoparasites, such as insects, and endoparasites such as nematodes and other worms. Domesticated animals, such as cats and dogs, are often infested with one or more of the following ectoparasites:                fleas (e.g. Ctenocephalides spp., such as Ctenocephalides felis and the like);        ticks (e.g. Rhipicephalus spp., Ixodes spp., Dermacentor spp., Amblyoma spp., and the like);        mites (e.g. Demodex spp., Sarcoptes spp., Otodectes spp., and the like);        lice (e.g. Trichodectes spp., Cheyletiella spp., Linognathus spp. and the like);        mosquitoes (Aedes spp., Culex spp., Anopheles spp. and the like); and        flies (Hematobia spp., Musca spp., Stomoxys spp., Dermatobia spp., Cochliomyia spp. and the like).        
Fleas are a particular problem because not only do they adversely affect the health of the animal or human, but they also cause a great deal of psychological stress. Moreover, fleas may also transmit pathogenic agents to animals and humans, such as tapeworm (Dipylidium caninum).
Similarly, ticks are also harmful to the physical and psychological health of the animal or human. However, the most serious problem associated with ticks is that they are vectors of pathogenic agents in both humans and animals. Major diseases which may be transmitted by ticks include borrelioses (Lyme disease caused by Borrelia burgdorferi), babesioses (or piroplasmoses caused by Babesia spp.) and rickettsioses (e.g. Rocky Mountain spotted fever). Ticks also release toxins which cause inflammation or paralysis in the host. Occasionally, these toxins are fatal to the host.
Likewise, farm animals are also susceptible to parasite infestations. For example, cattle are affected by a large number of parasites. Parasites prevalent among cattle in some regions are ticks of the genus Rhipicephalus, especially those of the species microplus (cattle tick), decoloratus and annulatus. Ticks such as Rhipicephalus microplus (formerly Boophilus microplus) are difficult to control because they lay eggs in the pasture where farm animals graze. This species of ticks is considered a one-host tick and spends immature and adult stages on one animal before the female engorges and falls off the host to lay eggs in the environment. The life cycle of the tick is approximately three to four weeks. In addition to cattle, Rhipicephalus microplus may infest buffalo, horses, donkeys, goats, sheep, deer, pigs, and dogs. A heavy tick burden on animals can decrease production and damage hides as well as transmit diseases such as babesioses (“cattle fever”) and anaplasmosis.
Animals and humans also suffer from endoparasitic infections including, for example, helminthiasis which is caused by of parasitic worms categorized as cestodes (tapeworm), nematodes (roundworm) and trematodes (flatworm or flukes). These parasites adversely affect the nutrition of the animal and cause severe economic losses in pigs, sheep, horses, and cattle as well as affecting domestic animals and poultry. Other parasites which occur in the gastrointestinal tract of animals and humans include Ancylostoma, Necator, Ascaris, Strongyloides, Trichinella, Capillaria, Toxocara, Toxascaris, Trichiris, Enterobius and parasites which are found in the blood or other tissues and organs such as filarial worms and the extra intestinal stages of Strogyloides, Toxocara and Trichinella. 
Another endoparasite which seriously harms animals is Dirofilaria immitis, also known as Heartworm. The most common hosts are dogs and cats but other animals such as ferrets and raccoons may also be infected. The parasitic worm is transmitted by the mosquitoe bites, which carry the heartworm larvae. The adult worms live in the major blood vessels of the lung, causing inflammation of the blood vessels and potentially resulting in heart damage and early death. In advanced infections, the worms enter the heart as well.
Recently, anthelmintic compounds with activity against various endoparasitic species were reported in WO 2009/077527 A1, WO 2010/115688 A1, WO 2010/146083 A1 and EP 2 468 096 A1 (all incorporated herein by reference). Although many parasitic infections can be treated with known antiparasitic compounds and compositions, there is a need for new parasiticidal active agents and veterinary compositions and methods with improved efficacy, bioavailability, and spectrum of coverage to protect animals against endoparasites and/or ectoparasites. This invention addresses this need.